Alert archive / California / Flash Flood Warnings in 2021
Flash Flood Warning 122, NWS Las Vegas, NV
NWS Las Vegas, NV issued this flash flood warning at Aug 30, 2021, 2:55 PM PDT for San Bernardino County, California. It was in force for 3 hr. 1 report came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Aug 30, 2021, 2:55 PM PDT (21:55 UTC)
- Expired
- Aug 30, 2021, 6:00 PM PDT
- In force
- 3 hr
- Issued by
- NWS Las Vegas, NV
- Area
- Storm-based polygon
- Damage threat
- Considerable
- Flood severity
- None
County San Bernardino County, CA
The radar
The Santa Ana Mts radar (KSOX), 134 km from the middle of the area, began a volume at 21:58 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Aug 30, 3:20 PM PDT | FLASH FLOOD | 4 N Twentynine Palms, CA | CITY OF TWENTYNINE PALMS REPORTED ROADWAY DAMAGE DUE TO FLASH FLOODING ALONG INDIAN TRAIL ROAD BETWEEN ADOBE ROAD AND MESQUITE SPRINGS ROAD. TIME ESTIMATED BY RADAR. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
San Diego, CA (KNKX), launched 12:00Z, 9.9 hours before the alert went out and 177 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1798 m above ground
- 0-6 km bulk shear
- 13 kt
- 0-1 km storm-relative helicity
- 1 m²/s²
- 0-3 km storm-relative helicity
- 45 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
743
WGUS55 KVEF 302155
FFWVEF
CAC071-310100-
/O.NEW.KVEF.FF.W.0122.210830T2155Z-210831T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
255 PM PDT Mon Aug 30 2021
The National Weather Service in Las Vegas has issued a
* Flash Flood Warning for...
Southern San Bernardino County in southern California...
* Until 600 PM PDT.
* At 255 PM PDT, Doppler radar indicated thunderstorms producing
heavy rain across the area from of Twentynine Palms, Joshua Tree
and Yucca Valley. Flash flooding is ongoing or expected to begin
shortly.
HAZARD...Life-threatening flash flooding. Thunderstorms
producing flash flooding.
SOURCE...Radar.
IMPACT...Life-threatening flash flooding of low-water
crossings, creeks, normally dry washes and roads.
* Some locations that will experience flash flooding include...
Twentynine Palms, Yucca Valley, and Joshua Tree.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 3410 11658 3414 11647 3421 11644 3426 11644
3432 11648 3436 11640 3447 11640 3460 11604
3448 11570 3404 11568 3404 11600 3408 11600
3408 11604 3411 11604 3412 11605 3412 11626
3408 11626 3408 11644 3404 11647 3404 11662
FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
$$
JA2 follow-up statements
568
WGUS75 KVEF 302324
FFSVEF
Flash Flood Statement
National Weather Service Las Vegas NV
424 PM PDT Mon Aug 30 2021
CAC071-310100-
/O.CON.KVEF.FF.W.0122.000000T0000Z-210831T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
424 PM PDT Mon Aug 30 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 6 PM PDT THIS EVENING
FOR SOUTHERN SAN BERNARDINO COUNTY...
At 424 PM PDT, Doppler radar indicated thunderstorms had dissipated
across the area from Twentynine Palms to Joshua Tree. However, heavy
rain that fell before 4 PM will cause flash flooding of some
low-water crossings in the warned area.
HAZARD...Life-threatening flash flooding. Thunderstorms producing
flash flooding.
SOURCE...Radar.
IMPACT...Life-threatening flash flooding of low-water crossings,
creeks, normally dry washes and roads.
Some locations that will experience flash flooding include...
Twentynine Palms and Joshua Tree.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 3410 11658 3414 11647 3421 11644 3426 11644
3432 11648 3436 11640 3447 11640 3460 11604
3448 11570 3404 11568 3404 11600 3408 11600
3408 11604 3411 11604 3412 11605 3412 11626
3408 11626 3408 11644 3404 11647 3404 11662
FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
$$
JA123
WGUS75 KVEF 310054
FFSVEF
Flash Flood Statement
National Weather Service Las Vegas NV
554 PM PDT Mon Aug 30 2021
CAC071-310104-
/O.EXP.KVEF.FF.W.0122.000000T0000Z-210831T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
San Bernardino CA-
554 PM PDT Mon Aug 30 2021
...FLASH FLOOD WARNING WILL EXPIRE AT 6 PM PDT THIS EVENING FOR
SOUTHERN SAN BERNARDINO COUNTY...
Flooding from heavy rainfall that occurred earlier this afternoon in
the Twentynine Palms and Joshua Tree areas is no longer expected to
pose a threat.
LAT...LON 3410 11658 3414 11647 3421 11644 3426 11644
3432 11648 3436 11640 3447 11640 3460 11604
3448 11570 3404 11568 3404 11600 3408 11600
3408 11604 3411 11604 3412 11605 3412 11626
3408 11626 3408 11644 3404 11647 3404 11662
$$
JAThe office that day
Everything else NWS Las Vegas, NV issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 29, 6:53 PM PDT | Flash Flood Warning | VEF | San Bernardino | 3 hr |
| Aug 30, 3:28 AM PDT | Flash Flood Watch | VEF | San Bernardino | 59 hr |
| Aug 30, 1:17 PM PDT | Flash Flood Warning | VEF | San Bernardino | 3 hr |
| Aug 30, 2:37 PM PDT | Flash Flood Warning | VEF | San Bernardino | 3 hr |
Nearby
Flash Flood Warnings in California, 2021Every flash flood warning in 2021
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.